#include <bits/stdc++.h>

#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz:" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = 1e9 + 7;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

struct Graph {
    Graph(const int n)
    {
        edge.resize(n);
    }
    void addEdge(const int from, const int to)
    {
        edge[from].push_back(to);
        edge[to].push_back(from);
    }
    vector<vector<int>> edge;
};

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N, M;
    cin >> N >> M;
    Graph g(N);
    using P = pair<int, int>;
    vector<P> edge(M);
    for (int i = 0; i < M; i++) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        g.addEdge(a, b);
        edge[i] = make_pair(a, b);
    }

    vector<int> dist1;
    vector<bool> isdist1(N, false);
    for (const int neighbor : g.edge[0]) {
        dist1.push_back(neighbor);
        isdist1[neighbor] = true;
    }
    vector<int> passnum(N, 0);
    vector<int> prev(N);
    for (const int from : dist1) {
        for (const int to : g.edge[from]) {
            if (to == 0) {
                continue;
            }
            passnum[to]++;
            prev[to] = from;
        }
    }

    for (const auto& e : edge) {
        const int u = e.first;
        const int v = e.second;
        if (passnum[u] == 0 or passnum[v] == 0) {
            continue;
        }

        if (passnum[u] > 1 and passnum[v] > 1) {
            cout << "YES" << endl;
            return 0;
        } else if (passnum[u] > 1) {
            if (prev[v] == u) {
                continue;
            } else {
                cout << "YES" << endl;
                return 0;
            }
        } else if (passnum[v] > 1) {
            if (prev[u] == v) {
                continue;
            } else {
                cout << "YES" << endl;
                return 0;
            }
        }
        if (isdist1[u] or isdist1[v]) {
            continue;
        }
        if (prev[u] == prev[v]) {
            continue;
        }
        cout << "YES" << endl;
        return 0;
    }
    cout << "NO" << endl;

    return 0;
}